Telescope force offsetting mechanism for a steering column assembly

The following description relates to vehicle steering systems and, more particularly, a mechanism to offset telescope force of a steering column assembly.

A vehicle, such as a car, truck, sport utility vehicle, crossover, mini-van, marine craft, aircraft, all-terrain vehicle, recreational vehicle, or other suitable vehicles, include various steering systems to carry out steering maneuvers. These steering systems typically include a steering column assembly for translating steering input to an output that interacts with a steering linkage to ultimately cause the vehicle wheels to turn. The steering column assembly must balance durability, safety, and ease of use while accommodating various design constraints. A design factor in steering column assemblies is the telescope force, which is the force required to adjust the axial position of the column, particularly in adjustable and collapsible steering columns. The force required to telescope a steering column assembly is typically symmetric in each direction when the column is horizontal.

Telescope effort is influenced by several parameters, including the angle of the column and the mass distribution of components mounted to the column. As the column angle increases (i.e., as the steering column assembly becomes more inclined away from a horizontal orientation to position the steering wheel in a convenient location for grasping by a driver), gravitational and inertial forces contribute more significantly to the resistance encountered during telescoping “out” movement. When telescoping “out” (i.e., toward the driver), a vertical component of force is higher than when the column is oriented closer to horizontally. Similarly, when mass is concentrated higher (i.e., closer to the driver) in the steering column assembly, the increased moment amplifies resistance, making adjustment more difficult for the user.

These factors become particularly relevant in vehicles with significant mass present near the driver, steeply inclined steering column assemblies, or advanced steering assist mechanisms, where user experience and ergonomic considerations are important. The aforementioned issues introduce challenges for compliance with OEM requirements for maximum telescope effort and telescope effort consistency. Therefore, there is a need for improved steering column assembly designs that mitigate these effects to maintain smooth and efficient telescopic adjustment in both axial telescoping directions, while accommodating modern vehicle architectures.

According to one aspect of the disclosure, a steering column assembly includes an upper jacket, a lower jacket, a hand wheel actuator disposed between an end of the upper jacket and a steering input device, and an offsetting mechanism. The upper jacket is telescopingly adjustable within the lower jacket between a retracted column position and an extended column position. The offsetting mechanism comprises a spring extending from a first end to a second end and a compensation component. The spring is configured to provide a biasing force at the second end of the spring that reduces gravitational effects on the steering column assembly during the telescopic adjustment. The compensation component comprises a sloped surface disposed within an interior of the upper jacket. The sloped surface is non-parallel with a longitudinal axis of the upper jacket and the second end of the spring operably slides on the sloped surface of the compensation component during the telescopic adjustment.

According to another aspect of the disclosure, the biasing force is larger in the retracted column position than in the extended column position.

According to another aspect of the disclosure, the sloped surface of the compensation component is integrally formed with or operatively coupled to the upper jacket.

According to another aspect of the disclosure, the sloped surface is angled at a predetermined angle from the upper jacket. The predetermined angle is based on an angle of the upper jacket in relation to a horizontal plane and weight of the steering column assembly.

According to another aspect of the disclosure, the spring is a rake spring.

According to another aspect of the disclosure, the steering column assembly further comprising an adaptor operatively coupled to the hand wheel actuator and the adaptor is disposed between the hand wheel actuator and the upper jacket.

According to another aspect of the disclosure, the compensating component is integrally formed with the adaptor or operatively coupled to the adaptor.

According to another aspect of the disclosure, the sloped surface comprises two or more portions and each portion of the sloped surface has a different predetermined angle from the upper jacket.

According to another aspect of the disclosure, at least a portion of the sloped surface is non-planar.

According to another aspect of the disclosure, an offsetting mechanism for a steering column assembly includes a spring extending from a first end to a second end and at least partially disposed within an interior region of a jacket of the steering column assembly. The offsetting mechanism also includes a compensation component, wherein the compensation component comprises a sloped surface disposed within the steering column assembly, wherein the second end of the spring operably slides on the sloped surface of the compensation component during a telescopic adjustment, wherein the spring is configured to provide a biasing force at the second end of the spring that reduces gravitational effects on the steering column assembly during the telescopic adjustment.

According to another aspect of the disclosure, a steering column assembly includes an upper jacket. The steering column assembly also includes a lower jacket, wherein the upper jacket is telescopingly adjustable within the lower jacket between a retracted column position and an extended column position. The steering column assembly further includes a hand wheel actuator disposed between an end of the upper jacket and a steering input device. The steering column assembly further includes an offsetting mechanism. The offsetting mechanism includes a spring extending from a first end to a second end. The offsetting mechanism also includes a compensation component, wherein the compensation component comprises a sloped surface that is non-parallel with a longitudinal axis of the upper jacket, wherein the second end of the spring operably slides on the sloped surface of the compensation component during the telescopic adjustment, wherein the spring is configured to provide a biasing force at the second end of the spring that reduces gravitational effects on the steering column assembly during the telescopic adjustment.

These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims, and the accompanying figures.

The following discussion is directed to various embodiments of the disclosure. Although one or more of these embodiments may be described in more detail than others, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.

Referring initially to, a vehicleis generally illustrated according to the principles of the present disclosure. The vehiclemay be any vehicle, such as a car, a truck, a sport utility vehicle, a mini-van, a crossover, any other passenger vehicle, any commercial vehicle, or any other suitable vehicle. While the vehiclemay be a passenger vehicle having wheels and for use on roads, the principles of the present disclosure may apply to other vehicles, such as planes, tractors, boats, or other suitable vehicles. The vehiclemay include a propulsion system, such as an internal combustion system, an electric system, or combinations thereof.

The vehicleincludes a steering system. The steering systemmay be configured as a driver interface steering system, an autonomous driving system, or a system that allows for both driver interface and autonomous steering. The steering system includes a steering input device, such as a steering wheel, wherein a driver may manually provide a steering input by turning the steering wheel. A steering column assemblyincludes a steering columnthat extends along an axis. A hand wheel actuator (“HWA”)(which may also be referred to as an “emulator”) is provided in the steer-by-wire system and is used to provide feedback and assistance to the steering input deviceand to receive manual driver inputs for steering control.

The steering columnincludes one or more portions, for example, an upper jacketand a lower jacket. While two jackets are illustrated and described, it is to be appreciated that a single jacket or three or more jackets may be provided in some embodiments. Regardless of the number of jackets, the jackets may be axially and or height adjustable to be moveable over a range of positions to meet user preferences for positioning of the steering input device.

A road wheel actuator (“RWA”)is in operative communication with the hand wheel actuator. The road wheel actuatoractuates lateral maneuvers of the vehicle in response to inputs received from the hand wheel actuator. Each of the hand wheel actuatorand the road wheel actuatormay include a respective processor and controller or a single processor may be in communication with a respective controller of each of the hand wheel actuatorand the road wheel actuator. The road wheel actuatoris part of a system which includes an output that drives a rack, ball screw or any other cross-car oriented component that is operatively coupled to the road wheels.

Historically, a continuous mechanical connection spanning multiple components was utilized to connect the steering wheelto the vehicle road wheels. However, steer-by-wire systems have eliminated the need for an uninterrupted mechanical connection between the steering wheeland the vehicle road wheels. For example, a steering shaft which couples to the steering wheel and one or more additional shafts (e.g., intermediate shaft) is no longer needed in some systems. Advancements such as those outlined above present new opportunities and challenges in steer-by-wire systems. For example, certain components may be moved away from traditional locations to new locations within the system.

Referring to, the steering column assemblyis illustrated in more detail. The steering column assembly includes the steering input device, the hand wheel actuator, an adaptor, the upper jacket, the lower jacket, a spring, a column mounting bracket, and a compensating component(depicted in). The steering column assemblyis configured to allow for telescopic adjustments of the upper jacketrelative to the lower jacketto accommodate driver preferences while maintaining structural integrity and ergonomic performance. The steering input deviceis operatively coupled to a spindlewhich resides within the hand wheel actuatorand is mounted to an end of the steering column assembly. The steering input deviceis rotated in response to driver inputs and actuation by the hand wheel actuator. The steering input deviceserves as the primary interface for the user to control direction of the vehicle. The steering input devicemay be a steering wheel where a driver may mechanically provide a steering input by turning the steering wheel. The hand wheel actuatoris located between the steering input deviceand the adaptor. The motoris electrically connected to a controller, which receives the steering input from the steering input deviceto initiate movement. The controller may regulate the operation, speed, torque, and direction of the motor.

The adaptoris connected between the hand wheel actuatorand the upper jacketto provide a structural connection between the jackets,and the steering input device. The upper jacketand the lower jacketare permitted to move axially with respect to one another to allow the user to adjust the position of the steering input deviceand during an impact event for safety purposes. The relative axial movement is described herein as being telescoping, wherein the upper jackettelescopes within the lower jacketover a range of axial positions from an extended column position to a retracted column position. The upper jacketsupports the steering input deviceand the motor, allowing for controlled extension and retraction between the extended column position and the retracted column position. The interface between the upper jacketand the lower jacketincorporates low-friction surfaces or bearing elements to reduce resistance during adjustment. The lower jacketis fixed to the vehicle, providing a stable base for column movement.

As shown in, the force from friction to telescope in (to the retracted column position) and telescope out (to the extended column position) are similar when the steering column assemblyis horizontally oriented. As shown in, the force required to telescope in is lower than the force required to telescope out because the steering column assemblyis angled and a force of gravity is acting on the steering wheel assembly. As the angle of the steering column assemblyincreases, i.e., as the steering column assemblybecomes more inclined toward the driver, and the mass increases in the end of the steering column assemblyproximate to the steering input device, the force required to telescope in decreases and the force required to telescope out increases. Placement of the hand wheel actuatornear the “top” of the steering column assembly, such as adjacent to the steering input device, exacerbates the disparity between the telescope effort force required for telescope in vs. telescope out movement.

Referring to, the offsetting mechanism disclosed herein includes the springand a compensating component. The compensating componentmay be a component which is separately formed from the adaptorand the upper jacket, and operatively coupled to the adaptorand/or the upper jacket. Alternatively, the compensating componentmay be integrally formed with the adaptoror the upper jacket.

The compensating componenthas at least a portion thereof which is disposed within an interior region defined by the upper jacket. More specifically, a sloped surfaceof the compensating componentis located within the interior region of the upper jacket. The sloped surfaceis referenced as “sloped” herein due to its angular orientation relative to a longitudinal axis of the upper jacket. In particular, the sloped surfaceis not parallel to the longitudinal axis of the upper jacket. An angle, (Ø) (depicted in), between the sloped surfaceand the longitudinal axis of the upper jacketis provided. The extent of the angle () based on the sloped surfaceis dependent on the spring force necessary to offset the force of gravity, which will be described herein.

In this embodiment, the springis a rake spring disposed within the interior region of the upper jacket. The springhas a first endand a second end. The first endof the springis attached to the column mounting bracket, which is attached to a vehicle structure to mount the steering column assemblywithin a vehicle. The second endof the springslides on the sloped surfacewhen the upper jackettelescopes in and telescopes out. The springis configured to assist with telescopic adjustment by providing a controlled biasing force (spring force) that reduces the force of gravity when telescoping the upper jacketrelative to the lower jacket. As the upper jacketis telescoped in, the second endof the springslides on the sloped surfacetoward the adaptor. As the second endof the springslides on the sloped surface, the springproximate to the first endbends which creates more spring force at the second endof the spring. The closer the second endof the springslides toward the adaptor, the more the springbends proximate to the first end. The more the springbends, the more spring force created at the second endof the spring. Therefore, the spring force increases as the upper jacketis telescoped from the extended column position to the retracted column position. The spring force from the springin combination with the offsetting mechanismreduces (offsets) the force of gravity as shown in.

As shown inand expressed in the below equation, the spring force of the springand the angle (Ø) are influenced by the weight of the components from the upper jacketto the steering input deviceand an angle (Ø) of the steering column assembly. This relationship is mathematically expressed as:×sin(Ø)=×sin(Ø)×cos(Ø)where Wis the weight of the components from the upper jacketto the steering input device, Øis the angle of the steering column assemblyrelative to horizontal, Øis the angle between the sloped surfaceand the longitudinal axis of the upper jacket, and Fis the spring force from the spring.

In an alternative embodiment, depicted in, the springis a telescope effort spring disposed within the upper jacketand the lower jacket. The first endof the springis attached within the lower jacketand the second endof the springslides on the sloped surfacewhen the upper jackettelescopes in and telescopes out. In another alternative embodiment, depicted in, the springis a lift spring attached to the bottom of the lower jacketat the first end, and slides on the sloped surfaceat the second end. In this particular embodiment, the compensating componentmay be integrally connected to the bottom of the upper jacketor operatively connected to the bottom of the upper jacket.

In any of the embodiments disclosed herein, the sloped surfacemay be a planar surface or may be curved to provide various desired force assist profiles. In particular, the entirety of the sloped surfacemay be a single, common plane to form a fully flat surface. In other embodiment, the sloped surfacecomprises two or more planar portions where their respective angles (Ø) may be different at each portion. For example, the angle (Ø) at one portion of the sloped surfacecloser to the lower jacketis larger (more steep) than another portion of the sloped surfacecloser to the adaptor, or vice versa. In this embodiment, the angle (Ø) of the sloped surfacechanges as the second endof the springslides between the retracted column position to the extended column position. In yet another embodiment, at least a portion of the surfaceis non-planar to provide a curved surface which changes the spring force applied at different contact locations of the springand the surface.

Various modifications and variations of the disclosure are possible in light of the above teachings. It is contemplated that all features of all claims and of all embodiments can be combined with each other, so long as such combinations would not contradict one another. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.